Just noticed two little quirks:
While being logged out, the team-detail page ("team_display.php") is somehow shown with a bigger fonts size and the page source (it isn't displayed, probably because it is before the html-tag) contains "<b>Notice</b>: Trying to get property of non-object in <b>/mnt/hosting/www/burp_production/html/user/team_display.php</b> on line <b>38</b><br />".
The session details page also displays the following two notices while being logged out:
Notice: Trying to get property of non-object in /mnt/hosting/www/burp_production/html/burpuser/session.php on line 222
Notice: Trying to get property of non-object in /mnt/hosting/www/burp_production/html/burpuser/session.php on line 229
Both pages work normally though, so it isn't really much of an issue. Just thought it wouldn't hurt to mention it anyway.
Edit: And quirk three: After posting this thread I got redirected to "http://burp.renderfarming.net/forum_thread.php?id=2014#11302", which displayed the notice "Notice: Trying to get property of non-object in /mnt/hosting/www/burp_production/html/inc/forum.inc on line 274". Reopening the same link works without the notice, so I guess it is somewhat related to posting the post/thread. This is again just a display thing, like the other two ones.